In 1924 Oggins discreetly joined the Workers Party of America, in reality the American Communist Party, and two years later was sent to Europe on his first clandestine mission-probably as a courier, bearing money, passports and other documents. Nerma sensibly severed her party ties - perhaps under instructions - and in 1928 they left for their first joint sojourn in Europe. During the next decade, they were to spend more time in Germany and France than in America. Again, Meier effectively evokes the political ferment in Berlin and Paris, linking it with developments at "home" - as devout communists tried to think of it - in Russia. Later, Oggins was sent on solo missions to China and Manchuria.

Throughout those years, the Ogginses loyally performed whatever the Centre demanded, including aborting Nerma's first pregnancy (a child would have been operationally inconvenient at the time). Their tasks included the provision of safe houses and secret communications, spying on the Romanoffs in France and possibly helping with the massive Russian operation to forge millions of US banknotes. Oggins usually posed as a researcher, a dealer in objets d'art or a businessman.

Although little is known in detail of what they did, Meier is good on the political and intelligence background of their various missions, usefully charting the secret mayhem of Stalin's Moscow. He also conveys something of the ideological delusion that led so many otherwise decent human beings to blind themselves to what they saw and accept that political necessity justified all. Less appealing is the book's structure, which resembles a dramatised documentary with flashbacks and forwards, and conjecture sometimes presented as fact. Also, Meier's accounts of his research interviews - clearly important to him - are frustrating. Oggins is the story we want to know about, not Meier's quest.